Chemical procedures will be used to investigate aspects of the structure and function of lactose synthase and human serum transferrin. With lactose synthase, studies will be aimed at the elucidation of the amino acid sequence of a homogeneous form of the galactosyl transferase and the investigation of its binding sites for substrates and the regulatory protein alpha-lactalbumin. Present studies of the amino acid sequence of transferrin will be completed to evaluate proposals about its evolutionary development. These will be extended through an investigation of the disulphide bond arrangement and chemical modification procedures designed to identify residues in the sequence that constitute the metal binding sites.